Intrinsic Charge Polarization in Bi<sub>19</sub>S<sub>27</sub>Cl<sub>3</sub> Nanorods Promotes Selective CC Coupling Reaction during Photoreduction of CO<sub>2</sub> to Ethanol
Kousik Das, Risov Das, Mohd Riyaz, Arko Parui, Debabrata Bagchi, Ashutosh Kumar Singh, Abhishek K. Singh, C. P. Vinod, Sebastian C. Peter
Abstract
Abstract Obtaining multi‐carbon products via CO 2 photoreduction is a major catalytic challenge involving multielectron‐mediated CC bond formation. Complex design of multicomponent interfaces that are exploited to achieve this chemical transformation, often leads to untraceable deleterious changes in the interfacial chemical environment affecting CO 2 conversion efficiency and product selectivity. Alternatively, robust metal centers having asymmetric charge distribution can effectuate CC coupling reaction through the stabilization of intermediates, for desired product selectivity. However, generating inherent charge distribution in a single component catalyst is a difficult material design challenge. Here, a novel photocatalyst, Bi 19 S 27 Cl 3 , is presented which selectively converts CO 2 to a C 2 product, ethanol, in high yield under visible light irradiation. Structural analysis through transmission electron microscopy, X‐ray diffraction, X‐ray photoelectron spectroscopy, and X‐ray absorption spectroscopy reveals the presence of charge polarized bismuth centers in Bi 19 S 27 Cl 3 . The intrinsic electric field induced by charge polarized bismuth centers renders better separation efficiency of photogenerated electron–hole pair. Furthermore, charge polarized centers yield better adsorption of CO* intermediate and accelerate the rate determining CC coupling step through the formation of OCCOH intermediate. Formation of these intermediates is experimentally mapped by in situ Fourier‐transform infrared spectroscopy and further confirmed by theoretical calculation.